According to Wikipedia: The Gros-Horloge (Great-Clock) is a fourteenth-century astronomical clock in Rouen, Normandy. The mechanism is one of the oldest in France, the movement was made in 1389. Construction of the clock was started by Jourdain del Leche who lacked the necessary expertise to finish the task, so the work was completed by Jean de Felain, who became the first to hold the position of governor of the clock.